1. Field of the Invention
This invention relates to a surface treatment method of a metal member including copper and a surface treatment device, and in particular, this invention relates to a surface treatment method of a metal member and a surface treatment device at the time of manufacturing the metal member such as a strip material, a wire material.
In addition, this invention relates to a cleaning technique capable of enhancing a cleaning degree of surfaces of various solid substances, for example, from a metal to which a mechanical processing is applied, such as a rolled steel plate, a cutting-worked product, to a semiconductor wafer to which a dry etching process is applied, and in particular, this invention relates to a cleaning nozzle that can be appropriately used for a degreasing cleaning of a metal strip and a metal plate including copper after the mechanical processing and a cleaning method of a surface of a solid substance using the cleaning nozzle and a cleaning device.
2. Description of the Related Art
A method of manufacturing a metal stripe including a copper stripe and a metal wire including a copper wire include a method that a raw material copper wire is processed so as to have a predetermined cross-section shape by a cold rolling, and then an extraneous matter on a surface thereof is removed from the surface by a cleaning treatment. The extraneous matter on the surface includes a lubricating oil used for a rolling process and a metal powder (a copper powder) that occurs in the rolling process.
FIG. 13 is an explanatory view schematically showing a conventional surface treatment device of a metal material, in which a metal strip 1a from a metal strip reel 1 before cleaning is fed from an uncoiler 11, and the metal strip 1a is passed through a surface treatment room 21 for cleaning so that a surface of the metal strip 1a is cleaned and an extraneous matter on the surface of the metal strip 1a is removed, and the metal strip 1a is dried in the drying treatment room and then is wound by a reel 2 of an uncoiler 12.
Conventionally, as a method of removing the extraneous matter in the surface treatment room 21, there is a technique (related art 1) that a lubricating oil on an object to be cleaned is removed by immersing the object in an organic solvent so as to dissolve the lubricating oil in the solvent, for example, as disclosed in non-patent literature 1. The non-patent literature “Readily available cleaning technique” also discloses a technique (related art 2) that a fine particle is removed by irradiating an object to be cleaned with an ultrasonic wave in a liquid.
In addition, there is a technique (related art 3) that a two fluids spray is sprayed, for example, this technique is disclosed in patent literatures 1 to 6. Also, there is a technique (related art 4) that a two fluids spray formed of water vapor and water liquid is used, for example, this technique is disclosed in patent literatures 7 to 9. Also, there is a technique (related art 5) that water vapor and spray water are discharged into a surface to be processed, for example, this technique is disclosed in patent literature 10. Also, there is a technique (related art 6) that a high pressure jet is used, for example, this technique is disclosed in a patent literature 11. These techniques are used in combination as necessary.    Patent literature 1: JP-B-2959763    Patent literature 2: JP-B-3498837    Patent literature 3: JP-A-1998-156229    Patent literature 4: JP-A-2005-294819    Patent literature 5: JP-A-2005-109112    Patent literature 6: JP-A-2006-255603    Patent literature 7: JP-B-3860139    Patent literature 8: JP-A-2001-250773    Patent literature 9: JP-A-2003-249474    Patent literature 10: JP-A-2007-216158    Patent literature 11: JP-A-1998-92707    Patent literature 12: JP-A-2003-154205    Non-patent literature 1 “Readily available cleaning technique” (Kogyo Chosakai Publishing Co., Ltd., 2001, p. 262, p. 138)
A problem with the related art 1 is that there is a possibility that in accordance with volatilization of the organic solvent, a working environment contamination and an air pollution are caused.
According to an Air Pollution Control Law revised in 2005, it requires to reduce a volatile organic compound (hereinafter referred to as VOC) generation amount by 30% from 2000 levels by the year 2010.
The copper strip and the copper wire have a long length as a whole, and even if they are wound around a reel or the like, the reel can not help having a large diameter and width, so that it is difficult to house the whole materials in a sealed device.
Due to this, generally, the reel of the copper strip or the copper wire is disposed in a feeding device located at outside of the sealed device, and the copper strip or the copper wire is introduced into the inside of the sealed device from an inlet so as to be processed, and then it is fed to outside of the sealed device from an outlet, so that it is wound around a new reel by a winding device or the like located at outside of the sealed device.
Namely, as explained in FIG. 13, the inside of the surface treatment room 21 is communicated with atmosphere via at least two open parts of the inlet and the outlet, so that the surface treatment room 21 can not be sealed. Consequently, in order to recover the organic solvent, it is necessary to introduce an equipment that is capable of sucking in such a large air volume that the organic solvent does not leak from the open parts, and further, a new problem is caused, that the organic solvent recovered is needed to be treated by a treating operation.
In case of using water instead of using the organic solvent in order to solve the above-mentioned problem, a new problem is caused, that a surface of the metal is oxidized. When a surface of the metal material including copper is oxidized, problems are caused in subsequent processes, that for example, in a coating process of resin, an adhesion between the resin and the metal is reduced, and in a plating process, holes referred to as a pit are generate.
A problem with the related art 2 is that cleaning power is not sufficiently high. When an output of the ultrasonic wave is increased in order to enhance the cleaning power, new problems are caused, that possibility that an ultrasonic wave oscillator is broken is heightened and cost for keeping the device is increased.
A problem with the related art 3 is that when gas and liquid are brought contact with each other, due to this, the liquid evaporates and a temperature is lowered by that an evaporative latent heat is removed. Generally, since the higher the temperature is, the more the viscosity of the liquid is lowered, similarly, the higher the temperature is, the faster the diffusion speed of contaminant into the cleaning liquid is. Consequently, in order to heighten the cleaning power, it is effective that the temperature of the cleaning liquid is heightened, but in case of using the related art 3, it is difficult to heighten the temperature. In addition, there is a problem that a large quantity of gas is consumed, so that a gas discharge equipment is needed to be increased in size.
A problem with the related arts 4 and 5 is that the cleaning power is insufficient. Any of the patent literatures 7 to 10 does not disclose removal of an oily liquid such as a rolling process oil adhering to the metal material. The patent literatures 8 and 9 disclose a removing method of a resist, and taking it for example, the minimum time necessary for the removal is read as not less than 30 seconds, for example, from FIG. 5 of the patent literature 9, but generally, a metal strip including a copper strip as an object to be cleaned is subjected to the cleaning treatment while being moved at a speed that is more than 10 m/min in case of a low speed and is more than 100 m/min in case of a high speed. If the cleaning time of 30 seconds is needed, it is necessary that a length of a cleaning zone is at least 5 m, so that the equipment is needed to be increased in size and an increase in investment is brought.
A problem with the related art 6 is that a large-scale device is needed. The patent literature 11 discloses a method of discharging a cleaning liquid pressured to not less than 5 MPa toward a surface to be cleaned, but a large-scale equipment for pressuring up to the above-mentioned pressure is needed, and a plant and equipment investment is increased.
In addition, a metallic product such as a steel plate, a screw material, a gear, a copper strip, a copper foil, a copper wire is manufactured by a mechanical processing such as a rolling work, a cutting work, a drawing work, and is formed so as to have a predetermined cross-section shape, and then an extraneous matter on the surface thereof is removed by a cleaning treatment. The extraneous matter on the surface includes a lubricating oil used for processing and a metal powder that occurs in the processing.
In addition, a wafer when a semiconductor device is manufactured, and a glass substrate (a glass substrate for liquid crystal) on which electric parts for driving a liquid crystal element are formed are processed by forming a thin film material on the surface by a sputtering, a chemical vapor deposition (CVD), or the like, pattering a mask material such as a photo resist further formed in a film on the thin film material by photolithography and then carrying out a dry etching process. After that, the mask material is removed and cleaned, and via an inspection process if necessary, the processing moves toward the next process of a film formation of the thin film material. The extraneous matter on the surface as an object to be cleaned includes residues of the mask material, reaction products in the dry etching process, foreign substances transferred in accordance with coming into contact with transport mechanism parts.
As a conventional removal method of the extraneous matter, there is a technique that a two fluids spray is sprayed, for example, this technique is disclosed in the above-mentioned patent literatures 1 to 6.
In addition, as a conventional removal method of the extraneous matter to the metal strip and the metal plate including copper, there are a technique that a lubricating oil on an object to be cleaned is removed by immersing the object in an organic solvent so as to dissolve the lubricating oil in the solvent, and a technique that a fine particle is removed by irradiating an object to be cleaned with an ultrasonic wave in a liquid, for example, as disclosed in the non-patent literature 1.
A problematic point caused when the techniques of the patent literatures 1 to 6 is used for the cleaning of the metal surface to which the mechanical processing is applied are that in accordance with the contact of a gas with a liquid, the liquid is vaporized, an evaporative latent heat is removed, and a temperature is lowered. Generally, the higher a temperature of the liquid is, the more a viscosity of the liquid is lowered, so that the higher the temperature is, the faster a diffusion of contamination substance into a cleaning liquid is. Therefore, in order to enhance the cleaning power, it is effective to heighten the temperature of the cleaning liquid, but in case of using the techniques of the patent literatures 1 to 6, it is difficult to heighten the temperature.
In addition, a problematic point caused when the techniques of the patent literatures 1 to 6 is used for the cleaning of the semiconductor wafer and the glass substrate for liquid crystal that an exhaust facility is needed to be grown in size so as to consume a large amount of gas. For example, the patent literature 4 discloses in paragraph 0029 that a desired gas flow rate is 10 to 100 L/min (normal), and discloses in paragraph 0031 that a desired liquid flow rate is 100 to 200 mL/min. A region covered by one cleaning nozzle is a circle having a diameter of approximately 1 cm at the largest, so that in particular, in case that a large area is cleaned as a case of the glass substrate for liquid crystal, a large number of nozzles are needed to be arranged. For example, since the glass substrate for liquid crystal referred to as the eighth generation has a dimension of 2160×2400 mm, in order to clean the whole surface, it is required that 216 cleaning nozzles are aligned in an array shape over the width of 2160 mm, arrays are arranged so as to sandwich the glass substrate for liquid crystal therebetween in the vertical direction, and the cleaning is carried out while the glass substrate for liquid crystal is moved so that the longitudinal direction of the glass substrate for liquid crystal corresponds to the running direction of the glass substrate. Namely, 432 cleaning nozzles are arranged in one cleaning chamber, in case that each of them discharges a gas of 100 to 200 mL/min, a total flow rate of the gas discharged into the cleaning chamber becomes 43 to 86 m3/min. In order to prevent mist from remaining in the cleaning chamber, a flow rate of the exhaust gas is needed to be not less than a flow rate of the gas discharged into the cleaning chamber, and the flow rate of the exhaust gas per one facility is increased up to 100 to 200 m3/min. In case that a plurality of the above-mentioned exhaust facilities that require a large amount of exhaust are installed in a factory, a burden that the whole of the factory bears for the exhaust facilities is extremely increased.